Method of manufacturing aluminum bronze-stainless steel bimetallic plates

ABSTRACT

A method of manufacturing bimetallic plates of aluminum bronze and stainless steel by loading by means of blow torch on a baseplate of austenitic or austeno-ferritic steel an intermediate layer of austeno-ferritic stainless steel of adequate composition to yield a ferrite content ranging from about 10 percent to about 20 percent, and loading said intermediate layer with aluminum bronze by arc-welding.

United States Patent METHOD OF MANUFACTURING ALUMINUM BRONZE-STAINLESSSTEEL BIMETALLIC PLATES 7 Claims, No Drawings US. Cl 219/137, 219/118,29/1963 Int. Cl 823k 9/00 Field of Search 2 l 9/ 137, 118, 76; 29/197,196.1, 195.5, 196.3

References Cited UNITED STATES PATENTS 4/1938 Swift 2l9/137X 2,158,7995/1939 Larson 214/76 2,787,699 4/1957 Jessen 219/137 2,916,602 12/1959Ea 1ss166. 219/76 3,393,445 7/1968 Ulam 219/196.1 FOREIGN PATENTS1,013,401 12/1965 0166113616111 219/76 OTHER REFERENCES Hard Facing withlnert & Gas Arc Welding" The Welding Journal, K. H. Koopman, January1949, pages 46- 52 The Welding Handbook, 1942, pages 882, 883

Primary Examiner-J. V. Truhe Assistant Examiner-George A. MontanyeAttorney-Wenderoth, Lind & Ponack ABSTRACT: A method of manufacturingbimetallic plates of aluminum bronze and stainless steel by loading bymeans of blow torch on a baseplate of austenitic or austeno-ferriticsteel an intermediate layer of austeno-ferritic stainless steel ofadequate composition to yield a ferrite content ranging from about 10percent to about 20 percent, and loading said intermediate layer withaluminum bronze by arc-welding.

METHOD OF MANUFACTURING ALUMINUM BRONZE- STAINLESS STEEL BIMETALLICPLATES The present invention relates to a method of manufacturingbimetallic plates of aluminum bronze and stainless steel, by loadingwith deposited metal by means of blow torch. This invention is alsoconcerned with bimetallic plates obtained by carrying out this method,notable those intended for use as tubular plates of heat transferdevices and the like.

Loading austenitic and austeno-ferritic stainless steels by depositingaluminum bronze by arc-welding is attended by the serious drawback ofproducing cracks under the bead in the base steel.

This cracking can be avoided by resorting to the method of thisinvention which permits of producing sound, highly reliable bimetallicplates, suitable notably for constructing tubular plates for heatingtransfer devices and the like (as currently used in case corrosion bysea water is to be feared).

The method of this invention consists in obtaining a bimetallic platefrom a baseplate of austentic or austeno-ferritic steel, by loading thisbaseplate by arc-welding with an intermediate layer of austeno-ferreticstainless steel of adequate composition to yield a ferrite contentranging from about percent to about 20 percent, then depositing aluminumbronze on said intermediate layer, also by arc-welding.

According to a specific but nonlimiting feature characterizing thisinvention, the intermediate layer of stainless austenoferritic steel isof the grade containing from 17 percent to 22 percent Cr, 8 percent to12 percent Ni, and 2 percent to 4 percent M0.

According to another feature characterizing this invention theintermediate layer consists of a steel grade already manufactured by theapplicant and assaying as follows:

Cu=l .5% All known and conventional arc-welding processes, whethermanual or automatic, may be used for depositing the abovedeftnedintermediate layer and loading same with aluminum bronze.

An advantageous application of this manufacturing method is notably theconstruction of tubular bimetallic plates of heat transfer devices andthe like.

Plates constructed according to the teachings of this invention arecharacterized by the following advantageous features in comparison withthose obtained through other known methods:

a sound alloy is definitely warranted,

a higher mechanical strength is obtained, as well as an improvedcorrosion-resisting structure.

in order to afford a clearer understanding of this invention, a typicalform of embodiment thereof will now be described by way of'example inthe case of the construction of four tubular plates for heat transferdevices having a diameter of 994 millimeters and utilizing sea water asa heat carrier medium.

For each plate the base metal is an austentic stainless steel assayingas follows: Cr=l 8 percent, Ni=l2 percent and C 0.030 percent, having athickness of 53 mm. An intermediate layer of austeno-ferretic stainlesssteel assaying as follows: Cr-=20 percent, Ni=8 percent, Mo=2.5 percent,Cu=l .5 percent and C 0.050 percent is loaded on the base layer or plateby arc-welding.

Then, a mm. thick layer of aluminum bronze is deposited thereon byarc-welding.

These plates are subsequently perforated by drilling therethrough 1,021holes having a diameter of three-quarters of an inch, without observingany crack formation, and bimetallic tubes of the same grade as thebaseplates are fitted through these holes. The resulting assembly isboth homogenous and economical.

What is claimed is: l. A method of manufacturing bimetallic plates ofaustenitic stainless steel and aluminum bronze, comprising the steps ofhard-facing by means of arc-welding on a baseplate of austeniticstainless steel an intermediate layer of austeno-ferretic stainlesssteel of suitable grade to obtain in said intermediate layer a ferritecontent ranging from about l0 percent to about 20 percent, andsubsequently hard-facing said intermediate layer with aluminum bronze byarc-welding,

2. A method of manufacturing bimetallic plates of austenitic stainlesssteel and aluminum bronze, comprising the steps of hard-facing by meansof arc-welding on a baseplate of austeno-ferritic stainless steel anintermediate layer of austeno-ferritic stainless steel of suitable gradeto obtain in said intermediate layer a ferrite content ranging fromabout l0 percent to about 20 percent, and subsequently hard-facing saidintermediate layer with aluminum bronze by arc-welding.

3. A method of manufacturing bimetallic plates of austenitic stainlesssteel and aluminum bronze, comprising the steps of hard-facing by meansof arc-welding on a baseplate of austenitic stainless steel in anintermediate layer of austenoferritic stainless steel having thefollowing composition: Cr=l 7 percent to 22 percent, Ni=8 percent to l2percent, and Mo=2 percent to 4 percent and subsequently hard-facing saidintermediate layer with aluminum bronze by arc-welding.

4. A method of manufacturing bimetallic plates of austenitic stainlesssteel and aluminum bronze, comprising the steps of hard-facing by meansof arc-welding on a baseplate of austeno-ferretic stainless steel anintermediate layer of austeno-ferritic stainless steel having thefollowing composition: CR=17 percent to 22 percent, Ni=8 percent to 12percent and Mo=2 percent to 4 percent, and subsequently hardfacing saidintermediate layer with aluminum bronze by arcwelding.

5. A method of manufacturing bimetallic plates of austenitic stainlesssteel and aluminum bronze, comprising the steps of hard-facing by meansof arc-welding on a baseplate of austenitic stainless steel anintermediate layer of austeno-ferritic stainless steel having thefollowing composition:

Si=0.5% Mn=0.5% C|=20.0% Ni=8.0% Mo=2.5% Cu=l .5% and subsequentlyhard-facing said intermediate layer with aluminum bronze by arc-welding.

6. A method of manufacturing bimetallic plates of austenitic stainlesssteel and aluminum bronze, comprising the steps of hard-facing by meansof arc-welding on a baseplate of austeno-ferritic stainless steel anintermediate layer of austeno-ferritic stainless steel having thefollowing composition:

C==0.05% Si=0.'5% Mn=0.5% Cr=20.0% Ni=8.0% Mo=2.5% Cu=l.5%, andsubsequently hard-facing said intermediate layer with aluminum bronze byarc-welding.

7. Bimetallic plates of a heat transfer device prepared by the method ofclaim 8.

2. A method of manufacturing bimetallic plates of austenitic stainlesssteel and aluminum bronze, comprising the steps of hard-facing by meansof arc-welding on a baseplate of austeno-ferritic stainless steel anintermediate layer of austeno-ferritic stainless steel of suitable gradeto obtain in said intermediate layer a ferrite content ranging fromabout 10 percent to about 20 percent, and subsequently hard-facing saidintermediate layer with aluminum bronze by arc-welding.
 3. A method ofmanufacturing bimetallic plates of austenitic stainless steel andaluminum bronze, comprising the steps of hard-facing by means ofarc-welding on a baseplate of austenitic stainless steel in anintermediate layer of austeno-ferritic stainless steel having thefollowing composition: Cr 17 percent to 22 percent, Ni 8 percent to 12percent, and Mo 2 percent to 4 percent and subsequently hard-facing saidintermediate layer with aluminum bronze by arc-welding.
 4. A method ofmanufacturing bimetallic plates of austenitic stainless steel andaluminum bronze, comprising the steps of hard-facing by means ofarc-welding on a baseplate of austeno-ferretic stainless steel anintermediate layer of austeno-ferritic stainless steel having thefollowing composition: CR 17 percent to 22 percent, Ni 8 percent to 12percent and Mo 2 percent to 4 percent, and subsequently hard-facing saidintermediate layer with aluminum bronze by arc-welding.
 5. A method ofmanufacturing bimetallic plates of austenitic stainless steel andaluminum bronze, comprising the steps of hard-facing by means ofarc-welding on a baseplate of austenitic stainless steel an intermediatelayer of austeno-ferritic stainless steel having the followingcomposition: C 0.05% Si 0.5% Mn 0.5% Cr 20.0% Ni 8.0% Mo 2.5% Cu 1.5%and subsequently hard-facing said intermediate layer with aluminumbronze by arc-welding.
 6. A method of manufacturing bimetallic plates ofaustenitic stainless steel and aluminum bronze, comprising the steps ofhard-facing by means of arc-welding on a baseplate of austeno-ferriticstainless steel an intermediate layer of austeno-ferritic sTainlesssteel having the following composition: C 0.05% Si 0.5% Mn 0.5% Cr 20.0%Ni 8.0% Mo 2.5% Cu 1.5%, and subsequently hard-facing said intermediatelayer with aluminum bronze by arc-welding.
 7. Bimetallic plates of aheat transfer device prepared by the method of claim 8.